It can be a disinformation superhighway and a worldwide web of lies for the unwary, but there are ways to filter out the hoaxes e-mails which blight your inbox.

At the end of July, an e-mail purporting to be an exclusive copy of Jamie Oliver's new cookbook, Naked Chef 2, arrived in millions of inboxes around the world.

I received it three times, each with the same covering note: "Attached is the NEW Jamie Oliver cookery book... Word is that he has annoyed his publishers so much that someone there has decided to send out his entire new book on e-mail!"

If you got it too, and headed for the kitchen to cook up some "Naked Chef exclusives", you've been had. The e-mail was a hoax.

"There's nothing original in the e-mail. It appears to come from a collection of his previous books," says Jess Ward of Penguin Books in London, which is pursuing the e-mail's elusive author for infringement of copyright.

The Oliver story was only the latest fabrication passed off as fact to wend its way around the web.

The net is alive with rumours and hoaxes, half-truths and untruths, modern myths and urban legends, that spread through e-mail lists, discussion groups and online publications.

Earlier in July, it was reported that heavy metal rockers Metallica were suing a Canadian rock band for "unsanctioned use" of two chords that Metallica have used since the 1980s: E and F.

A hoax, of course - though the story made its way on to respected radio stations in the US.

HOW TO SPOT A HOAX

Look for the telltale phrase, 'Forward this to everyone you know.'

And for statements like 'This is NOT a hoax' or 'This is NOT an urban legend' - they usually mean the opposite

Watch out for overly emphatic language, the frequent use of UPPERCASE LETTERS and multiple exclamation points!!!!!!!

Look for logical inconsistencies, violations of common sense and obviously false claims

Look for subtle or not-so-subtle jokes, indications that the author is pulling your leg

Check for references to outside sources. Hoaxes will not typically name any, nor link to websites with corroborating information

Check if the message has been debunked by websites that cover net hoaxes

Source: Urban Legends and Folklore by David Emery (Urbanlegends.about.com)

Other recent classics include the story about a health department in the US state of Oregon seeking a Klingon interpreter - to assist mental health patients who only speak in the fictional language created for the Star Trek TV series.

The origin of that tall tale was an article in the Oregonian newspaper, which reported that Klingon had been added to a list of 55 languages that some psychiatric patients claimed they could speak, though "in reality, no patient has yet tried to communicate in Klingon".

Yet by the time the story had spread around the web, eventually picked up by news organisations in May 2003, the notion the Oregon was looking for someone fluent in Klingon had acquired the status of fact.

In June, the web buzzed with rumours that Powergen, the British gas and electricity company, had chosen an unfortunate domain name for its new Italian division: Powergenitalia.com.

Powergen doesn't even have an Italian division. The Powergenitalia site belongs to an Italian company that sells battery products - and no, not sexual ones.

Internet rumours are often the result of jokes gone wrong. Many still believe that Donald Rumsfeld, the US defence secretary, referred to France and Germany as an "axis of weasels" in the run-up to the Iraq war in March.

He did no such thing. That "news" story was the comic creation of the satirical website, Scrappleface.

Don't give up the day job, no Klingon speakers needed

Franco-American tensions generated another e-mail-spread rumour in July. "Did you hear about France demanding the American soldiers buried over there be dug up and removed from the land?" the e-mail began. "They sent a note to our government saying 'Come and pick up your trash'."

These entirely concocted claims were received by millions - and no doubt believed by thousands.

So are we more gullible than ever? According to Barbara Mikkelson, who runs the rumour-busting website Snopes.com, "there has never been a time in history when there wasn't a lot of rumours and wild stories. The internet simply gives us a written record of such things".

Mikkelson and her husband David have been running Snopes from their home in Los Angeles since 1995, during which time she has developed a keen eye for what makes an effective rumour.

"There has to be some measure of plausibility. And it has to contain elements that a large number of people will agree or empathise with. Otherwise it is unlikely to spread."

Sure you can use E and F

According to Mikkelson, although rumours may be irritating and mislead people, they can also play an important role in attempting to make sense of modern society.

"Rumours can be our way of coping with the confusion of difficult times. That's why you saw so many rumours come up in the aftermath of the 11 September terrorist attacks."

Rumour-mongering was rampant after 9/11. A widely distributed email claimed that 4,000 Jewish employees did not turn up for work at the World Trade Center on the morning of the attacks, implying that they had prior knowledge of what was to happen - a story still believed by some Muslims in the Middle East.

Other rumours included claims that Nostradamus had predicted the attacks; that the devil's face could be seen in photographs of the collapsing towers; and that an unburnt Bible was found in the wreckage of the Pentagon.

DEBUNKED MYTHS

Marilyn Manson (above) was NOT in the TV show The Wonder Years

Charles Manson did NOT audition to be in The Monkees - he was in prison and too old

Walt Disney was NOT cryogenically frozen after his death

Source: Snopes

"People were trying to make sense of a world that had just gone mad," says Mikkelson. "They were looking for ways to explain what looked like inexplicable events."

According to Frank Furedi, a professor of sociology at the University of Kent at Canterbury, rumours are the products of a society that lacks shared values and common means for understanding events.

"People are selective in their engagement with rumours," he says. "People select ones that affirm their beliefs and make sense of their suspicions."

Barbara Mikkelson's advice to web users is to be more selective still. "Look at something and appraise it intelligently," she says. "And only pass it on if you are convinced it's true."